Open-Label Extension Study of Marstacimab: Pfizer Has Reported a Fatal Event
Wolfgang Miesbach, Professor of Medicine at Frankfurt University Hospital, shared a post on LinkedIn:
“Safety Signal: Perioperative management with anti-TFPI therapy!
Pfizer has reported a fatal event in the open-label extension study of marstacimab (B7841007). The participant (haemophilia A with inhibitors) passed away on Dec 14 following a cerebellar infarction and cerebral haemorrhage.
What was the clinical context?
The event occurred perioperatively during minor surgery. The patient was receiving marstacimab prophylaxis + recombinant Factor VIIa (rFVIIa).
The Challenge
As we advance rebalancing therapies (anti-TFPI), this underscores the critical physiological threshold of thrombin generation. The synergy between TFPI inhibition and bypassing agents—particularly in surgical contexts—remains a complex therapeutic balance.
Status
While marstacimab is approved in the EU for non-inhibitor patients with haemophilia A and B, this event in the inhibitor cohort has triggered an immediate review of surgical management protocols by regulators and the DMC.
Full adjudication to better understand the safety margins and risk mitigation is needed for these novel agents.”
Title: WFH and NBDF statement on severe adverse event with marstacimab rebalancing agent for hemophilia
Read the full paper here.
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